1. Field of the Invention
The present invention relates to a keyboard device, and more particularly, to a structure preferably applicable to a keyboard device having a transparent case.
2. Description of the Prior Art
Recently, as an example of well-designed keyboard, provided is a keyboard where appearance-constituting members such as an upper case, a lower case and key tops are formed of transparent resin or translucent resin. This type of keyboard has a transparent or translucent appearance, through which the internal structure of the keyboard main body can be seen, thus the keyboard is of a good design.
FIG. 1 shows an example of the structure of this type of keyboard device. The keyboard device 1 has a keyboard main body 3 to which a large number of key tops 2 are attached, and a case which accommodates the keyboard main body 3. The case is composed of a combination of an upper case 4 which covers the surface side of the keyboard main body 3 and which has a window 4a for exposing the key tops 2, and a lower case 5 which covers the rear surface side of the keyboard main body 3. In this example, the upper case 4 and the lower case 5 are formed of transparent resin. The key tops 2 of the keyboard main body 3 are supported on a metal support plate 6.
Further, the control board 7 which controls transmission/reception of various signals between the keyboard device and a computer main body or the like is provided under the keyboard main body 3. To prevent leakage of signals from the control board 7 or to block influence of extraneous disturbances on the control board 7, a shield case 8 having an opened top is attached so as to cover the control board 7 from the rear surface side of the keyboard main body 3. At this time, a bottom plate of the shield case 8, in contact with the bottom surface of the lower case 5, is fixed to the support plate 6 and the lower case 5. Further, a resin sheet 9, with its side facing the lower case 5 being coated, is bonded to a rear surface of the support plate 6.
In the above-described keyboard device, as the lower case 5 in addition to the upper case 4 is formed of transparent resin, the rear surface of the keyboard main body 3, and the shield case 8 and the like can be seen from the rear surface side of the keyboard device. Accordingly, as a well-designed keyboard, the color and appearance viewed from the rear surface side of the keyboard are carefully considered in the design. For example, the coated resin sheet 9 is bonded to the rear surface of the support plate 6 for this purpose. The tint of the coating of the resin sheet 9 is coordinated with that of the shield case 8 for color consistency. Further, the resin sheet 9 covers screws fixing various members on the rear surface of the support plate 6.
However, in each keyboard device, the occurrence of variation in size for manufacturing the shield case and slight distortion of the support plate cannot be avoided. As shown in a cross-sectional view of the keyboard device in FIG. 4, a small gap (denoted by a symbol S) may be formed between the edge of the shield case 8 and the support plate 6 (resin sheet 9) due to the above variation and distortion, and the appearance of the keyboard device viewed from the rear surface side is impaired by the existence of the gap S.
To prevent an occurrence of the gap, the height of side plate of the shield case may be designed to be greater than the conventional height. However, if the shield case is larger, the shield case and the support plate interfere with each other in a contact portion therebetween. As a result, portions of both members to be tightly bonded together may float, otherwise, upon application of force to bring them into close contact, the respective members may be distorted by the force.
The present invention has been made to solve the above-described problems, and has its object to provide a keyboard device having a structure where an occurrence of a gap between a rear surface of a support plate of a keyboard main body and an edge of a shield case is prevented, and having an excellent appearance even when viewed from a rear surface side of the transparent keyboard.
According to the present invention, the foregoing object is attained by providing a keyboard device comprising: a keyboard main body having plural key tops on a support plate; a control board provided on a rear surface side of the support plate; a blocking member provided on the rear surface side of the support plate so as to cover the control board; and a case, where at least a rear surface side being formed of transparent resin or translucent resin, accommodating the keyboard main body, the control board and the blocking member, wherein a resin sheet is provided on a rear surface of the support plate, and wherein the resin sheet is bonded to the support plate in a region at least except a region corresponding to an edge of the blocking member positioned on the rear surface side.
That is, one feature of the keyboard device of the present invention is that the resin sheet covering the rear surface of the support plate is not bonded to the support plate in a region corresponding to the edge of the blocking member positioned under the support plate. In this structure, as the resin sheet is not bonded to the support plate in the region corresponding to the edge of the blocking member, the sheet somewhat floats from the support plate. As a result, if the size of the blocking member is rather small or if a part of the support plate is somewhat recessed, i.e., a situation to cause a gap is provided as in the case of the conventional structure, a gap is not formed in a contact portion between the resin sheet and the edge of the blocking member, thus the keyboard device has an excellent appearance, even when viewed from the rear surface side. Since the gap caused by manufacturing variation is at most about 0.1 to 0.5 mm, the gap can be sufficiently compensated by the floating of the resin sheet from the support plate.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same name or similar parts throughout the figures thereof.